The present invention relates to a wireless video/audio transmission device and, more particularly, to a wireless video/audio transmission device having bi-directional communications function.
Along with continual progress of scientific technology, the development of wireless video/audio transmission device becomes full-blown everyday. Commercially available wireless video/audio transmission devices generally use 900 MHz or 2.4 GHz wireless communications channel. As shown in FIG. 1, a basic wireless video/audio transmission device 10 comprises an emitting device 12 and a receiving device 14. The emitting device 12 includes a sound processing circuit 16, a mixer 18, and a modulator 20. The sound processing circuit 16 is exploited to convert audio left and audio right into a sound signal, which is transferred to the mixer 18 along with a video signal captured by a video source. The sound signal and the video signal are modulated by the modulator 20 into a first carrier signal, which is then emitted to the receiving device 14. After a demodulator 22 in the receiving device 14 is used to demodulate the received carrier signal and a sound processing circuit 24 is used for processing sound, the restored sound is outputted by a speaker device and the restored video signal is outputted by a display.
Another kind of remote control type wireless video/audio transmission device in the prior art is the above basic wireless video/audio transmission device matched with the UHF emitting and receiving function for transmitting infrared signals of remote controller. As shown in FIG. 2, a 2.4 GHz emitting module 26 and a UHF receiving module 28 are disposed in an emitting device 12. A 2.4 GHz receiving module 30 and a UHF emitting module 32 are disposed in a receiving device 14. The actions of the 2.4 GHz emitting module 26 and the 2.4 GHz receiving module 30 are the same as those of the above basic wireless video/audio transmission device. An infrared receiving module 36, an optical converter 38, and a UHF modulator 40 are disposed in the UHF emitting module 32. The infrared receiving module 36 is used to receive an infrared signal emitted by the infrared remote controller. The optical converter 38 is used to convert the infrared signal into an electronic signal, which is then modulated by the modulator 40 into a second carrier signal to be emitted out. A UHF demodulator 42, an optical converter 44, and an infrared emitting module 46 are disposed in the UHF receiving module of the emitting device 12. After the UHF receiving module 28 receives the second carrier signal, the UHF demodulator 42 and the optical converter 44 are used to demodulate and restore it into an infrared signal, which is then emitted to remotely control the operations of the audio left and audio right sound sources and the video source.
The above two kinds of wireless video/audio transmission device can provide convenient video/audio transmission. Moreover, the remote control type wireless video/audio transmission device has additional remote control function and thus is more appreciated. However, it only has unidirectional remote control and unidirectional transmission and reception design, and cannot meet the requirements of some more advanced, complicated, and important applications, e.g., real-time bi-directional intercommunication of sound and security by discrimination codes. Therefore, this wireless video/audio transmission device cannot apply to the designs of bi-directional intercommunication at a doorbell and unlocking of a door by codes. Accordingly, the present invention aims to propose a novel wireless video/audio transmission device, which has, in addition to wireless video/audio transmission function, the advantages of bi-direction intercommunication and security by discrimination codes.
The primary object of the present invention is to propose a wireless video/audio transmission device having the functions of bi-directional intercommunication and security by digital codes. The wireless video/audio transmission device uses an emitting device to simultaneously modulate a video/audio signal and a control signal in a 2.4 GHz or 5.7 GHz channel and then transmit them to a receiving device. The receiving device demodulates the video/audio signal and the control signal and transmits them back to the emitting device in a UHF channel. A highly integrated bi-directional communications system is thus provided.
Another object of the present invention is to provide a wireless video/audio transmission device, which integrates a 2.4 GHz or 5.7 GHz channel and a UHF channel into the same device to accomplish bi-directional communications capacity of sound and digital control, and simultaneously has the advantage of unidirectionally transmitting video in the 2.4 GHz or 5.7 GHz channel.
According to the present invention, a wireless video/audio transmission device for bi-directional communications comprises an emitting device and a receiving device. The emitting device comprises a first channel emitting module and a second channel receiving module. The receiving device comprises a first channel receiving module and a second channel emitting module. Video, audio, and a digital control instruction are processed by a signal processing circuit of the first channel emitting module, and are emitted out by a first channel modulator and transmitted to a first channel receiving module at another place. The first channel demodulator in the first channel receiving module is used to demodulate the signal into video, audio, and an output instruction. On the other hand, after a digital control instruction and an analog audio signal are mixed by the second channel emitting module and modulated by a second channel modulator, the signal is emitted out and transmitted to the second channel receiving module. A second channel demodulator is used to demodulate the signal into a base-band signal, which is then restored back to an audio signal and an output instruction.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: